Optical phantom for resolution evaluation of non-contact corneal microscopy techniques.

We present the development of a corneal phantom designed to enable resolution assessment for non-contact corneal microscopy. The phantom was fabricated by casting a UV-curable epoxy mixed with 400-nm-diameter gold nanoparticles into a polydimethylsiloxane (PDMS) mold with a curved surface to achieve a cornea-like geometry. The radius of curvature of the final manufactured phantom was 8.14-8.17 mm with a refractive index of 1.39, similar to the adult human cornea. The optical phantom was used to evaluate the resolution of a prototype non-contact confocal microscope, the portable in vivo confocal ophthalmoscope (PICO). PICO images of the optical phantom allowed for evaluation of the resolution change as a function of depth.